Get to Know a Projection: Raisz’s Armadillo

Who wouldn't want to curl up with a Raisz Armadillo on a cold winter day? Image: NASA

Consider the armadillo. It’s a charming little critter whose appeal comes from its mix of familiar mammalian form and the oddity of its signature adaptation – an armored back. It’s an unexpected answer to the question of how to survive in a world full of hungry predators.

The Armadillo projection also combines the familiar with the unexpected. It portrays the spread of continents and oceans in a familiar way. But what gives it character and a dash of creativity, however, is a curved shell-like shape that recalls the leathery back of its mammalian namesake.

The Armadillo projection was invented in 1943 by a Hungarian immigrant named Erwin Raisz. Raisz had trained in his home country as an engineer, but after coming to New York he enrolled in Columbia University and followed his passion to become a mapmaker. He was insatiable. While pursuing his Ph.D., he taught cartography (one of the first formal classes in the U.S.), and paid the bills by hand-drawing maps for a company on the Upper West Side. After he graduated, he was offered a job as a professor and map curator at the newly minted Institute of Geographic Exploration at Harvard University (IGE).

I would be a poor narrator if I didn’t digress and tell you about this colorful little slice of academia, which played a key role in an interesting chapter of the history of geography that’s had long-lasting implications.

In 1929, Alexander Hamilton Rice made an offer to Harvard University: He’d pay for a cartographic institute independent from the school’s geography program if he could be the director and a professor. Despite his reputation (Rice was an eccentric explorer, which made him seem unreliable to the administration), the school agreed, probably because he was married to the rich Titanic widow Eleanor Widener, whose previous donation had built the school its flagship library. Rice was bit of a scoundrel, though, and would often play hooky from his duties and run off to explore some uncharted fork of the Amazon.

But the good times couldn’t last forever. After World War II, the school was facing budget cuts. The school’s president, James Conant, already had a grudge against geography because it wasn’t, as he saw it, scientific enough. Conant also took a dim view of the rumored homosexuality of the chair of the geography department, a man named Derwent Whittlesey. Rice’s antics didn’t help, either. In 1947 geography was axed. Even though the IGE was initially insulated from the decision because of Rice’s money, the old adventurer finally decided he’d had enough of the school’s politics, and closed the doors in 1950.

Many other colleges around the country followed Harvard’s assertion that “Geography is not a university subject,” and shuttered or severely cut their programs as well. This decision is often blamed for the poor geographic knowledge of most Americans and the reason for the discipline’s ongoing identity crisis.

Ironically, by the time Harvard’s leadership had cast geography aside as science-less, Erwin Raisz had spent 20 years turning IGE into a hotbed for scientific cartography. He pioneered the use of aerial photography and radio waves to make maps, invented cartograms (purposefully distorted maps that showed the value of supposedly “ungeographic topics as races, languages, religions, population donsity [sic], poverty, disease, hunger…” wrote the Harvard Crimson in 1944), and wrote the first English-language textbook on cartography. He also made a series of maps the US Army used for logistical operations in World War II, and his hand-drawn landform maps are legendary for their detail and beauty (and still available on the cheap from his family’s website).

And of course, he invented the Armadillo. Unlike the real-world usefulness of his other inventions, it seems like Raisz made the Armadillo just to scratch a geometric itch. He wanted a map with the lively look of a globe, but without the hopeless warping that comes from putting a globe directly onto paper. In a 1943 paper introducing the projection, he wrote “The solids to which a parallel and meridian network can be applied are infinitely varied: similar projections can be drawn on forms resembling a bean, a lima bean, or a scallop,” In other words, he wanted his flat map to look 3-dimensional.

Raisz’s hand-drawn landform maps, like this one of Alaska, make the Earth look like something out of Lord of the Rings. Photo: Nick Stockton

The Armadillo projection isn’t just the peeled skin of a globe, it’s the peeled skin of a geometric donut called a torus. Raisz called this map orthoapsidal, a made up word that refers to the projection’s light source and it’s shape.

Ortho is for orthographic, the geometric term for showing a 3-dimensional object in two dimensions. To grok this, it’s useful to think about map projections as shadows cast through a glass globe. The shape of the projection (also known as the globe’s shadow) depends a lot on where that hypothetical light source is coming from. For orthographic projections, cartographers pretend the light source is coming from something very distant and very big (like a sun), effectively striking every part of the globe at the same angle. (For reference, stereographic projections are made when the light comes from a single source on the opposite side of the globe, and gnomonic projections are nauseating and sprawling because the light comes from the globe’s center). The apse part of the name refers to the projection’s curved, hollow shape, which reminded Raisz of the domed vaults in cathedral ceilings.

A lot of thought went into the Armadillo map, but compared to Raisz’s other creations, it’s not all that practical. Like many other cartographers, Raisz wanted the Mercator overthrown, but he never proposed the Armadillo as a replacement. In fact, the biggest compliment he ever gave it was that it “showed more land in proportion to sea than any other world map.” As a world map, it’s not that it’s bad, it’s just not nearly as good as others (Robinson, Winkel-Tripel, or Eckert IV come to mind) for showing the globe as a single and relatively undistorted image.

Raisz put a lot of mathematic rigor into his seemingly whimsical creation, and he is probably more responsible than any other one person for making geography a modern, technical science. But behind all that rigor was a guy who loved looking at maps. The Armadillo is mostly a clever curiosity. But it’s still a great map for people who love looking at maps.